The invention relates to a cooling system, particularly for a motor vehicle, coupled to a refrigerating circuit via a refrigerant/coolant heat exchanger and to a method for cooling a heat source by means of the cooling circuit.
Cooling systems of this type are used, for example, in motor vehicles with an electric drive (for example, with a fuel cell) or hybrid drive, in order to protect a battery functioning as an energy store against excessive heating. It is variously known, in this context, to cool the battery by means of a cooling circuit which functions at the same time as an air conditioning system for cooling supply air for a vehicle interior.
JP 2002 313 441 A discloses a cooling system in which the battery is cooled by means of circulating air which is itself cooled by a specific evaporator which is arranged, parallel to an evaporator for cooling supply air for a vehicle interior, in a specific refrigerating circuit branch of an air conditioning system. By means of an air control flap, the battery can also be cooled selectively by means of ambient air which is subsequently discharged outward again.
In a cooling system described in JP 11 040 212 A, a battery is cooled as a function of the temperature of the battery and of an outside air temperature either directly by means of outside air or else by means of air which is branched off from a supply air stream for a vehicle interior which is routed conducted through an evaporator of a vehicle air conditioning system.
JP 2002 352 866 A describes a cooling system having a cooling circuit and a refrigerating circuit which are coupled to one another via a refrigerant/coolant heat exchanger. Located in the cooling circuit are a battery to be cooled and an air/coolant heat exchanger for cooling the coolant by means of ambient air. The air/coolant heat exchanger can be bypassed by the coolant in a controllable way via a bypass line. An evaporator for cooling vehicle interior supply air is located in a refrigerating circuit branch parallel to the branch of the refrigerant/coolant heat exchanger. In this cooling system, the cooling of the battery may take place, on the one hand, via the air/coolant heat exchanger by means of ambient air and, on the other hand, via the refrigerant/coolant heat exchanger by means of the refrigerating circuit. In the refrigerating circuit, a changeover valve is provided, which controls whether the refrigerant flows via the refrigerant/coolant heat exchanger or via the evaporator for cooling the supply air.
It is the object of the invention to provide a cooling system and a cooling method, by means of which an effective cooling of a heat source, in particular a vehicle battery, is possible with high cooling energy efficiency.